Rotary wet classifier



July 11, 1933. H, HARDINGE 1,917,300

ROTARY WET CLASSIFIER Original Filed July 10, 1929 4 Sheets-Sheet 1 FIG. 1.

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July 11, 1933. H. HARDINGE ROTARY WET CLASSIFIER Original Filed July 10, 1929 4 Sheets-Sheet 2 l w! z r icl iii-ii "li I. in l- I: I. if!- Evwctoz y 1933- H. HARDINGE ROTARY WET CLASSIFIER Original Filed July 10, 1929 4 Sheets-Sheet 5 Svwemtoz l/wuqw: wan/1V6! a; 4% flt toM um b 01111121, Mum Y Jul 11, 1933.. H, HARDINGE 1,917,300

ROTARY WET CLASS IFIER Original Filed July 10, 1929 4 Sheets-Sheet 4 FIG. 10.

Qvwemtoz 351 Etta/1401 0 AMMM Patented July 11,.1933

UNITED STATES) PATENT OFFICE HABLOWE HARDINGE, OF YORK, PENNSYLVANIA, ASSIGNOR T HARDINGE COMPANY, INCORPORATED, OF YORK, PENNSYLVANIA, A CORPORATION 01 NEW YORK ao'jramr wn'r omssmma Application filed July 10, 1929, Serial No. 877,094. Renewed December 9, 1981.

Among the objects of this invention is to provide a wet classifier which is capable of use for classifying many different materlals, which has substantial ranges of use for different materials and which may be prepared or adjusted for a certain use within a wide range of uses without the requirement of major changes. 4

Another object of the invention is to provide a classifier by which a close separatlon of materials may be obtained and in which the product is uniformly fine and the oversize is clean in that it contains a minimum amount of the fines which should go out with the product.

Another object of the invention is to provide a rotary wet classifier which is susceptible of close regulation of operating characteristics and in which the various adjustments for bringing about regulation of operating characteristics may be made quickly and with ease.

' Other objects and advantages will be pointed out hereinafter in the description of the invention and in the claims.

Structural features embodying my invention are illustrated in the drawings, in which:

Fig. 1 is a longitudinal sectional elevation of one form of classifier.

Fig. 2 is a view taken from the left of the classifier illustrated in Fig. 1 with some of the parts broken away.

Fig. 3 is a section on line 33 of Fig. 1.

Fig. 4 is a detail of the left end of a classifier showing 90 and 45 buckets for lifting oversize material.

Fig. 5 is a view taken from the left of F i 4. Fig. 6 is a cross-sectional detail illustrating lifting buckets having adjustable vanes.

Fig. 7 is a side view of a wheel carrying adjustable buckets which are pivotally mounted.

Fig. 8 is a detail of an adjustable bucket of Fig. 7. I

Fig. 9 is a modification of a rotary wet classifier embodying the principles of the invention.

Fig. 10 is a section on line 1010 of Fig. 9.

The rotary classifier has an outer or'main The progress of material through the classi-' fier is such that the coarse or oversize material is carried toward the front end of-the drum from whence it is removed by buckets'which may take any one of various forms. The fine material is carried out from the classifier at its rear end by water overflowing therefrom.

A chute 13 is provided for introducing within the classifier liquid and material carried thereby which is to be classified according toa desired degree of fineness and this chute 13- may extendv to about the center of the inner drum 11 or it may terminate nearer to or farther away from the end wall 14 of the inner drum. It will be appreciated that since the liquid and material introduced within the classifier must travel toward the rear end of the classifier before the coarse particles thereof may be separated definitely from the fine particles, the ultimate position of termination of the chute 13 constitutes a factor affecting the operation of the classifier even though but a limited degree of adjustment is possible.

The end wall 14 of the inner drum is ape tured for the purpose of inspection and for other conveniences, but the aperture 15 is of such size as to prevent the passage of any liquid or material.

The water line of the classifier is normally above the lowermost point 16 of the edge of the discharge opening 17, and, since it is customary to have the classifier in a slightly tllted position with'its rear end lower than its front end, the direction of flow of water will be towards the rear end even though no extra or washing water is introduced in the main drum as hereafter to be explained. The finer material of the material introduced to the classifier by means of chute 13 has a tendency to float and is carried out of the classifier at its discharge end. Depending upon the use to which the fine material is to be put, it is collected by one means or another as the water and fine material leave the conical surface 18.

Ports 19 are provided in the wall of the inner drum 11 through which coarse or oversize material may find its way. The size of these ports and the velocity of the water flowing up through the ports are factors which afiect the coarseness of the material capable of passing from the inner drum 11 to the main drum 10. In order to control the size of the ports 19 adjustable closure plates 20 are provided, one for each of the ports. As the classifier is rotated by means to be described hereinafter, the coarse material which has fallen through the ports 19 will be urged toward the front end of the classifier by means of flights 12. Inorder to produce and maintain a flow of water or of other liquid in a direction opposite to the progress of the coarse material along the inner wall of the main drum water is provided by means of a conduit 21 which discharges within the outer or main drum at its front end. This water flows from left to right, Fig. 1, through the main drum and sufficient space is left between the tops of the flights 12 and the outer wall of the inner drum for permitting the fine material loosened from the coarse material to be carried along with the water up'through ports 19 and out of the classifier at its discharge end.

The water entering the classifier through conduit 21 has no other course to follow than between the main drum and the inner drum and thence up through ports 19. If the closure plates 20 are so positioned as to leave the ports 19 wide open the velocity of the water through these ports is low and as a consequence relatively fine material is allowed to pass down into the main drum. If

. the ports 19 are partially closed and/or an increased amount of water is permitted to enter the classifier through conduit 21, the finer particles will be prevented from falling through the ports 19 into the main drum. As a result of an increase in the velocity of the water flowing up through ports 19, there will be a gradual accumulation of very fine particles together with particles which will not quite pass down through the ports and all of this accumulation will eventually overflow through the discharge opening 17 inasmuch as the specific gravity of the mass of liquid and material in the inner drum in the vicinity of ports 19 will be raised, and, under these conditions, coarser particles will float out with the fine particles. A similar effect may be produced by increasing the rotational speed of the classifier for, with an increase in speed, there will be a corresponding increase in the degree of agitation and an accompanying retardation of the settling rate.

As previously explained the coarse particles which drop through ports 19 are caused to travel toward the front end of the classifier by means of flights 12. The water passing from the front end of the classifier toward the rear end washes these coarse particles clean of fines, dirt, slime, etc. Since the water travels from left to right between and above the screw flights, it will be understood that the speed of rotation of the drum is a factor determining the rate of travel of. the coarse particles from the right end of the classifier to the left end and consequently is a factor in determining the degree of washing produced by the counter-current of water.

I have devised several means by which the coarse material may be removed from the front end of the classifier. In Figs. 4 and 5 I have illustrated a series of buckets 22, 23 which are carried by the main drum. As illustrated, these buckets are arranged alternately in sets with one set 22 placed at 90 with the inner wall of the drum and the other set 23 placed at 45 with the inner wall of the drum. Buckets which are fixed to the main drum may take diverse forms, as for example, similar to the cups 23a illustrated in Fig. 9.

In the event that it becomes desirable to control the degree of fineness of the product flowing from the classifier through its discharge opening 17 by providing mechanism for enabling changes in the speed of rotation of the classifier it may be desirable to regulate the rotational speed of the buckets independently of the classifier. Accordingly, for such operations as make it desirable for rotating buckets at different speeds from that of the drum, I mount individual buckets 24 upon a wheel 25, Figs. 1 and 2. Wheel 25is carried by a shaft 26 mounted in suitable bearings 27, 28. As wheel 25 is rotated buckets 24 pick up the oversize at the bottom of the main drum 10 and dump it into a hopper 29. Wheel 25 carries a peripheral screen 30 which constitutes the bottom portions of the several buckets 24.

The screen openings may be so small that none of the oversize particles may pass through or they may be somewhat larger than the finer particles of the oversize to be removed, but, in the latter case, due to the large quantity of oversize being elevated in comparison to the screen area, fine oversize will be picked up by these buckets. The coarse oversize acts somewhat like a filter bed which permits water to percolate through but which retains particles of oversize finer than the maximum oversize that would normally pass through the screen. It can readily be seen that under certain conditions there is an appreciable time element which is required for permitting proper settling of the oversize in the buckets and for effecting proper de-watering after each bucket has been elevated above the water line.

Another type of oversize discharge devices in which a peripheral screen is used in illustrated in Fig. 6. In Fig. 2 the buckets 24 are each fixed relatively to the screen 30, and

in Fig. 6 the buckets comprise adjustable vanes 33 which are pivotally mounted so that their angular positions relative to the screen ma be varied at will. One side of a bucket of ig. 6 constitutes the end wall 35 of the main drum and the other side of each bucket is a fixed plate 36 individual to a bucket. While I have illustrated a peripheral screen 34 with the bucket construction illustrated in Fig. 6, it is apparent that'it is not necessary to have a screen forming a wall portion of a bucket which has an adjustable vane 33.

When 'it is possible to control the rotation of the buckets at such a speed as to permit the oversize material to settle and when the buckets are so shaped that the oversize, after it has settled will remain in the bottom of the bucket and permit the water to decant over the top of the bucket until a certain point is reached where the oversize will commence to flow or drop out of each bucket, the construction providing vanes-3'3 enables the form of the bucket to be varied at will to suit conditions. In those cases where it is not possible to control the point at which the oversize will commence to flow or drop out of the buckets it is advantageous to provide a hopper 29 which has a variabe extension 37, Fig. 6. This extension 37 is adjustable so that the material spilling from the buckets and intended to be gathered by the hopper 29 may be varied at will. Thus, by putting the end of the extension 37 close to the line of buckets all of the spilling above the end of the extension will be caught whereas if the end of the extension is pushed back toward the hopper a greater amount of the liquid and material carried by the buckets will be spilled back into the classifier before the bucket has risen high enough to spill all such cases adjustments can be readily be made between the speed of the buckets and the point of discharge of the buckets and the proportion of the discharge material collected by the extension. It will readily be appreciated that the control enabled by such construction offers a means of control of the character and moisture of the oversize delivered from the classifier.

' Figs. 7 and 8 illustrate another method by which separate buckets 38 may be employed on a wheel 39. These buckets have .a bottom vane 40, side walls 41 and are pivotally carried by the wheel 39. By virtue of the pivotal connection 42 the space between the inner wall 43 of the main drum and the edge 44 of the bucket, Fig. 8, may be varied at Will to suit desired requirements. In ordinary operation the rotation of the drum will. be

faster than the rotation of the buckets and there will be a tendency for the drum when going faster than the buckets to keep the oversize in the buckets but at the same time the space between the edges 44 of the buckets and the inner wall 43 of the main drum will permit liquid to flow out and thus de-watering is secured without the use of screens.

In the modification of the classifier illustrated in Fig. 9 the main drum 45 is conical and has a tapered end in a direction opposite to that of the inner drum 46 which is also tapered. The material and water to be classified is introduced by means of a chute 47 and flows to the right within the inner drum. The fine material is carried off by flotation at the discharge opening 48 and the coarse material settles in that portion 49 of the classifier which is disposed beyond the rear end of the inner drum 46. By terminating the inner drum 46 short of the rear end of the main drum 45 a greater settling area is provided than is the case where ports in the inner drum are relied upon for permitting the coarse material to drop from the inner drum to the main drum. The oversize material setting out and resting on the inner wall of the main drum tends to travel to the left and in order to reach the rear end of the main drum it must pass through a restricted course wh i'h is formed by ports 50. These ports 50 may be adjusted in area by means of adjustable plates 51, Fig. 10. As described hereinabove, in connection with ports 19 of Fig. l, the adjustable area of ports 50 enables the velocity of the water passing through the main drum from the 'front end to the rear end to be regulated. The water is introduced within the classifier by means of the conduit-52.,

In the classifiers illustrated in Figs. 1 and 9' it is to be appreciated that the discharge openings 17 and 48 may bevaried in diameter and that the amount of solution within the classifier is determined by the size of the openings. The greater-the diameter the less will be the solution and, other conditions being equal, there will be a greater tendency to overflow coarser particles since the settling volume is smaller.

It frequently is desirable, particularly in the type of classifier illustrated in Fig. 1, to have the discharge end slightly lower than the oversize end. This is so when it is desired to have as much volume of solution at the discharge end as possible and as little volume of solution at the oversize end. The small amount of solution at the oversize end allows a greater time for the oversize to remain in the buckets before being discharged and hence tends to provide a better de-Watering condition. Less solution at the oversize end allows the water coming from conduit 21 to be more effective in washing fine particles from the oversize as it passes between the inner drum and the main drum.

Classifiers of the type disclosed herein find use in almost every metallurgical operation where a mill grinds ores. They are also used for a great many industrial purposes and may be used to wash sands, and other minerals. They may also be used in connection with mills where they act in the capacity of classifiers which pass on as a product material of a given fineness but which .returns the over-.

size material for further grinding. When used in this latter manner it may be found to be convenient to provide an elevating wheel 53 having buckets and in which the hopper 29 discharges, Figs. 1. and 2. This elevating wheel is of larger diameter than the main drum 10 and it therefore provides a means by which oversize may be raised to a high position so as to discharge into a chute 54 by which material may be discharged by gravity to a mill (not shown).

Roller treads 55, 56, Fig. 1, are provided which rest upon pairs of rollers 57, 58 near the ends of the classifier. These rollers are mounted upon shafts 59, 60, Fig. 3 which are operated by a motor 61 and intermediate drive 62. This same motor 61 may also be used for driving the bucket wheel shaft 26, and the driving mechanism 63 intermediate shaft 26 and the motor 61 may be so designed in relation to the gearing 62 as to enable the rotated at the same or bucket wheel 24 and the main drum 10 to be at different speeds, as desired.

The invention is capable of wide variation and relationship of parts without departure from the nature and principle thereof. I do notrestrict myself unessentially in the foregoing or other particulars, but contemplate such alterations and modifications within the scope of the appended claims as may be found advisable.

I claim:

1. In a classifier, the combination comprising a rotary main drum having end walls with apertures therein, a second drum within said main drum, said second drum having walls partitioning the interior of the second drum from the exterior of the second drum except for openings permitting the flow of liquid and material therethrough, means for introducing liquid and material to said second drum, means for permitting the removal of liquid and material from the classifier, and means for removing coarse material which has passed through said openings.

2. The combination set forth in claim 1 in which means are provided enabling regulation of the size of the openings.

3. In a classifier, the combination comprising a rotary main drum having end walls with apertures therein, a second drum w thin said main drum, said second drum having a wall at its front end preventing the flow of material between the drums and a plurality of openings permitting the flow of material from the second drumto the main drum, means for introducing liquid and material within said second drum forward of said openings, a discharge port rearward of said openings permitting removal of liquid and of material carried thereby, and means at the forward end of the main drum for discharging coarse material.

4. In a classifier, the combination comprising a rotary main drum, a second drum within said main drum, said second drum defining a chamber within itself and forming a chamber between the drums, and means for introducing liquid within said second chamber and permitting liquid to leave said second chamber and enter said first chamber, said means including openings between said two chambers and an overflow port through which the liquid may leave the classifier.

5. The combination set forth in claim 4 in which means are provided for enabling regulation of the velocity of the liquid entering the first named chamber.

6. In a classifier, the combination comprising a rotary main drum, a second drum within said. main drum, said second drum having a wallat its front end spaced from the front end wall of the main drum and openings connecting the chamber within the second drum and the chamber between the second drum and the main drum, means for introducing liquid and material into said second drum, a port permitting liquid and material carried' thereby to leave the classifier, and means between said main and second drums causing coarse material to be carried toward the front end of said main drum.

7 In a classifier, the combination comprising a rotary main drum, a second drum within said main drum, said second drum having a wall at its front end spaced from the front end wall of the main drum and openings connecting the chamber within the second drum and the chamber between the second drum and the main drum, means for introducing liquid and material into said second drum, a port permitting liquid and material carried thereby to leave the classifier, means within the main drum and outside of the second drum for removing coarse material from the main drum, and means for advancing material from the rear end of the main drum to its forward end as the drum is rotated.

8. In a classifier, the combination comprising a rotary main drum, a second drum therein, said second drum being closed against the passage of material at its forward end and defining a settling chamber having communication with the interior of the main drum I of said open rmittin the overflow of liquid and o f iiiateria'l carried thereby, means at the forward end of said main drum for removing coarse material, means for causing solid material to travel within said main drum from the vicinity of said openings to said last named means while permitting the flow of liquid in the main drum in the other direction, and means for introducing liquid to said main drum.

9. In a classifier, the combination comprising a rotary main drum, a second drum therein, said second drum being closed against the passage of material at its forward end and forming a settling chamber opening into said main drum, means for introducing liquid and material into said settling chamber forward of openings between said main and second chambers, a port permitting the overflow of liquid and of material carried thereby from the settling chamber, and means at the forward end of the main drum for removing coarse material.

10. The combination set forth in claim 9 in which the drums are conical and oppositely sloped with the small end of the main drum and the large end of the second drum at the overflow port end of the classifier.

11. In a classifier, the combination comprising a rotary main drum having end walls with apertures therein, a second drum within said main drum, said second drum having walls partitioning the interior of the second drum from the exterior of the second drum except for ports permitting the flow of liquid and material therethrough, means for introducing liquid and material to said second drum, and means at the front end of said main drum and exterior of the second drum for removing oversize material from the main drum, said means comprising buckets mounted for rotation, and means for rotating said main drum and last named means.

12. In a classifier, the combination comprising a rotary main drum, a second drum within said main drum, said second drum having a wall at its front end spaced from the front end wall of the main drum and ports connecting the chamber within the second drum with the chamber exteriorly of the second drum, means for introducing liquid and material to said second drum, and means between the front end walls of the drums for removing oversize material from the main drum, said last'named means comprising a Wheel with buckets thereon for lifting the oversize material from the main drum.

13. The combination set forth in claim 12 in which means are provided for permitting angular adjustment of the buckets in respect to the wall of the main drum.

14. The combination set forth in claim 12 in which means are provided for rotating the main drum and bucket carrying wheel at different speeds.

l5. In a classifier, the combination compr sing a rotary main drum, a second drum within said main drum, said second drum having a wall at its front end spaced from the front end wall of the main drum and ports connecting the chamber within the sec ond drum with the chamber exteriorly of the second drum, means for introducing liquid and material to said second drum, and means between the front end walls of the drums for removing oversize material from the main drum, said last named means comprising a wheel having a perforated periphery and vanes extending inwardly from the perforated periphery whereby material from the main drum may be lifted for discharging purposes. I

16. The combination set forth in claim 15 in which the vanes are angularly adjustable inhreslpect to the perforated periphery of the w ee 17. In a classifier, the combination com-- prising a rotary main drum, buckets mounted for rotation with said main drum, a hopper for receiving material from said buckets, and an extension adjustable at will, to receive more or less of the material split from said buckets depending upon the position of said extension.

18. In a classifier, the combination comprising a rotary main drum having end walls with apertures therein, a second drum within said main drum, said second drum havin walls partitioning the interior of the secon drum from the interior of the main drum except for ports permitting material to pass from the second drum to the main drum,

means for removing such material from the main drum,'and means for introducing liq uid into the main drum.

19. In a classifier, the combination comprising a rotary main drum having. end walls with apertures therein, a second drum within said main drum, said second drum having walls partitioning the interior of the second drum from the interior of the main drum except for ports permitting material to pass from the second drum to the main drum, 1

with apertures. therein, a second drum within said main drum, said second drum having walls partitioning the interior of the second drum from the interior of the main drum except for ports permitting material to pass from the second drum to the main drum,

means for introducing to said second drum liquid and material to be classified, means causing oversize material falling through said openings to travel toward one end of the main drum, means to remove the oversize material at the end of its travel through the main drum, and means for introducing liquid to the main drum so as to flow therein toward and through the openings in the second drum in a direction against the travel of the oversize material.

21. In a classifier, the combination comprising a rotary main drum having end walls with apertures therein, a second drum within said main drum, said second drum having walls partitioning the interor of the second drum from the exterior of the second drum except for openings permitting the flow of liquid and material therethrough, means for introducing liquid and material to said second drum, means for permitting the removal of liquid and material from the classifier, means for removing'coarse material which has passed through said openings, said last named means including buckets within said main drum, a hopper for receiving material from said buckets, and means for varying the hopper opening with respect to the discharge point of the buckets.

22. In a classifier, the combination comprising a rotary main drum, buckets mounted for rotation within said main drum, a hop per for receiving material from said buckets, and means for varying the hopper opening with respect to the discharge point of said buckets.

23. In a classifier, the combination comprising a rotary drum, means at one end thereof for removing material from said drum, said means comprising a perforated circular band and vanes for lifting material settling on said band and vanes, and a hopper for receiving material from said band and vanes, said hopper having provision for varying the hopper opening with respect to the discharge point of the material falling from said band and vanes.

24. In a classifier, the combination with two concentrically disposed drums, the inner drum being enclosed entirely by the outer drum and having a wall at the inner end thereof to prevent the discharge of material therethrough and an opening at the opposite end thereof roviding the sole communication between t e two drums, of means for introducing the material to the inner drum,

means for discharging the fines in one direction from the inner drum, and means for discharging the coarse in the opposite direction from the outer drum.

25. In a classifier, the combination with two concentrically disposed drums, the outer drum having end walls with apertures therein, the inner drum being enclosed entirely by the outer drum and having walls partitioning the interior thereof from the exterior thereof except for openings permitting the flow of liquid and material therethrough, of means for introducing liquid and material to said inner drum, means for discharging the liquid and fine material from one end of theclassifier, and means for removing coarse material which has passed through said openings from the opposite end of the classifier.

26. In a classifier, the combination with a rotary drum, of a material lifting wheel therein, buckets mounted on said wheel, and means for rotating said wheel independently of said drum.

27. In a classifier, the combination with a rotary drum, of a rotatable wheel therein for discharging material from said drum, buck-.

ets mounted on said wheel, and means for rotating the wheel at speeds difierent from that of the drum.

28. In a classifier, the combination with a rotary drum, of means at one end of said drum for removing material from the drum, said means comprlsing vanes angularly disposed in respect to the periphery of said drum, and means for adjusting the angular relation of said vanes.

29. In a classifier, the combination with a rotary drum, of means at one end of said drum for removing material from the drum and comprising vanes angularly adjustable in respect to the wall of said drum, and means for independently adjusting the angular positions of said vanes.

30. A classifier comprising a unitary body having concentrically disposed inner and outer chambers, the inner chamber being enclosed by the outer chamber and having a wall at the inner end thereof to prevent the discharge of material therethrough and a discharge outlet at the opposite end thereof, and ports connecting the chambers near the discharge outlet of the inner chamber.

In testimony whereof I hereto atfix my signature.

HARLOWE HARDINGE. 

